Can someone explain this ?

[Lonnie]

Hello

I've been reading Hoke and have learned lots from it but still left baffled by these contacts . My only conclusion is they has to be more than just silver in some of them . I had over 200 contacts I removed from 6 dry breakers that came out of Langley Research center in Hampton Va . Build date on the breakers was 1920 . Assuming all the contacts were the same I only had one shot with a handheld scanner and it was suppost to be 52% Ag 45% W and 3% Mo .

Forget a stannous test I get a rainbow of colors in most solutions . Some yellow solutions just turn a green blueish color but on many I get purple on the tip then blue in the middle with a yellow green on the bottom . Thats just sticking a Qtip in about half way on the cotton . Then turning it straight up and dropping one drop stannous on the end of it . Letting it run down wetting the rest of the cotton .

The yellow solutions that turn green blue I understand could be palladium but none of the test are conclusive enough to be sure . The reason I say that is because as I understand it when stannous is used I should first get a yellow color slowly turning green/blue . This just instantly turns to the blue green color .

Pictures are worth a 1000 words and below are just a few that kinda shows more than I could ever hope to explain with my english and understanding of this stuff .

This picture shows the last batch of contacts I processed . I cemented this grey stuff down with copper but it doesn't look like my other silver looks . Plus these metalic balls keep growing in the stuff .

Quite a few of them grew on top of the grey stuff and I could scoup them out with a spoon .

This pic shows them in a small beaker after removing them from the jar . I tried washing this up and when I did it turned back into the grey looking powder that cemented down the first time . What ever it is the stuff is heavy .

Plus when I get finished cementing silver down I can always get a white cloud with salt or a drop of Hcl . So I've been cementing all the silver doen I could and then bring the rest down with salt . I'm about certain my AgCl I've collected is a mixture of metals . I'm so new I really can't explain just why I feel this way but do . Again pictures are worth a 1000 words and might help me explain this feeling also .

I know people bound to think I'm crazy but do know 2 things for certain . 1) Ive done everything just like I was told to do them for silver . 2 ) I can see different results with my eyes . This picture shows a seperation after adding salt . The bottom layer is a off white yellow color while the upper layer turned purple .

The color purple is another thing that has me wondering . I understood AgCl would come down white then turning purple and then black . Mine has never turned black . I have quite a bit and it stayed purple . Plus I finally made it to the end of Hoke and was reading about the hazards and about stains .

She explains that people handling gold solutions get purple stains , people handling Silver solutions get black stains and yellow is from nitric . Well I'm not trying to get my hopes up or anything like that but only on 2 occasions have I had black stains . Once I had a yellow spot I'm guessing was from nitric but since the start you could color me purple . Out of all the small stains I ended up with most have been purple .

I hope the pics help someone to help me . I'm thinking my AgCl ?? should be washed in ammonia and that scares me thinking about mixing silver and ammonia . Any help with how to proceed would be appreachated .

Lonnie

 

[Lonnie]

Before anyone jumps in here and trys to help I'd like to mention a few more ( for lack of better word ) weird things that have happened while working these contacts . Out of about 15 batches so far I have managed to get silver everytime . However twice I had to add salt to bring it down it would not cement out .

So far I've had 3 messed up batches but silver did cement out the second time this happened . The first time something different took place I cemented down about the same amount as in this jar of black stuff . Jet black with little shinny glitters in it . It cemented just about like silver it would kinda moss over and I'd jiggle the copper and it would fall off with more cementing out . Not the first drop of silver cemented out in this batch .

I bought litmus paper thinking I'd left it to acidic but not really that acidic it tested about a 3 on the chart . So I filtered the black substance out and added salt and bingo I got a good layer of AgCl to come down . This messed up batch was easy to seperate the substances . Not like messed up batch number two .

Well I had a few batches that did great just like they should I even worked up about a pound of Sterling without a hitch everything going as I felt it should . Them bam I do a rather large batch for me and end up with about 1/2 quart of what ended up seperating into 3 different things . Silver cemented out in this batch but so did a light brown mud and a grey material that the best I could describe it was an oily , shimmering stuff .

I got the 3 different things seperated finally . It took me 2 weeks and about 15 gallons of water . My silver in this batch still looks dingy to me but the water I washed it with did finally clear up nice . It took a long time for the grey and brown mud to settle so I started and completed a few more batches without a hitch and again everything seemed to go just like I was told it would . Then bam this last batch again throws a curve ball at me . Luckley this last batch seems easy to seperate as none of the silver cemented down with it in this batch .

One small oddity about the way this cemented out that might lend a clue to someone more experienced . I'd place the copper bar in the jar hanging it over the rim of the jar and in most batches I'd just jiggle this a little and the silver would fall off and sink to the bottom . This last batch I did not have to touch .

Starting from the bottom of the copper bar it would start pealing off going up and would peal the whole cemented layer off and then straight to the top the stuff would go . It would float for a little while then sink . No sooner than one mossy layer would peal off another one formed to only peal off in a second or two . It repeated this untill I had the layer you see in the bottom of the jar and stopped .

After posting the first message of this thread I took a small amount of the acid solution and placed it in a test tube and added salt . Bingo I got a huge white cloud so they was silver in the batch it just wouldn't cement out and I'm kinda glad it never . If it had of it would have been very hard to seperate like the second time and that sucked big time . At least this way I can filter off the mud in the bottom and add salt and will have my silver seperated real easy .

Plus an updates in order concerning what I said earlier . I stated the metalic balls converted back to the brown mud . I'm not so sure thats the case I'm now thinking they just kinda busted up getting smaller . After trying to wash the stuff I covered the material with acid solution hoping the nice round balls would grow in the beaker . Between that acid layer and the brown stuff in the beaker it obstructed my view . This is what I poured off and added salt to and I can now see the shinny substance is still in the beaker it just looks more condensed than it first was .

Well thats about all I can think to add at this time .

 

[Lonnie]

Dag gum guys am I poison ?? 80 views and not even a word uttered . Surley the refining worlds not as baffled as I am being new and all . Anything anyone could suggest to give a direction to head in . I'm not wanting someone to hold my hand just point a blind guy in the right direction if you can .

Otherwise all I know to do is to get the test tubes washed up and start drying powders and find a solvent to take them up in solution . If I could get them to a point ( in acid solution) where I might get them tested and start figuring something out . I probably shouldn't even mention curve ball number 4 LOL .

At least it was kinda expected , or I should say at least it fits the change in process I made today . Looks promising so far but all this is so new and confusing it's probably iron .

 

[trashmaster]

I can only suggest that you go back langley ( if it is still there ) and researce the archives of what they were working on in that lab around that time.

When i first saw the pic's of the stuff growing in your container the first thing that popped in my head was BISMOUTH maby not spelled correct .. I don't know why as i have no chemical knowledge,, maby i seen a pic somewhere..

paul

 

[lazersteve]

Lonnie,

Tungsten can form yellow oxides with nitric.

Perhaps if you narrow your questions to be a little more specific without so many question in one (or three) posts you may get some responses.

Silver is easy to separate from most other metals simply using 35% nitric acid, heat, filtration, and finally copper. Are you certain the 'black specks' are not originating from your copper?

Maybe if you work with some small samples of the material to id what you have before you jump in head first. Sorting out problems on a small scale first seems like a lot simpler task to me.

Take a sample of the pregnant silver solution and add HCl one drop at a time stirring between each drop. When the drops no longer produce a curd like substance (silver chloride) stop the acid additions. Filter off the silver chloride (white that turns purple - not black). Be sure to filter until the solution is 100% clear of sediment.

Wash the silver chloride in nearly boiling water and filter it again. Repeat this step several times for purer silver chloride. Convert to silver metal using lye and sugar or acid and iron (videos on my website for both).

Now turn your attention to the liquid from the small test sample that you removed the silver chloride from. It should be 100% transparent and free of sediment or cloudiness. Note it's color and test a small sample of it with DMG and another with stannous chloride. Note the colors that you see.

Post photos of your results.

Steve

 

[Oz]

Lonnie,
I can’t sort out what you are doing in order to help you, and I imagine others are in the same situation. You are giving differing details on at least 3 batches and I can’t sort them out.

You stated “I’ve done everything just like I was told to do them”. Who told you what? Did you pick and choose between multiple posts for your procedure? This leaves me wondering what you did do. I can tell by your pictures you are mixing precipitates by changing procedures in mid stride.

Pick one type of scrap you have processed for silver and give great detail as to what you have done with pictures if possible.

 

[Lonnie]

Oz

" I can tell by your pictures you are mixing precipitates by changing procedures in mid stride "

You are absolutly wrong I haven't changed anything in these pictures or the procedure . This very last batch has had something done slightly different however it wont be finished up and ready to cement anything from untill about 11.00 in the morning ( 3-30-11 ) With exception of the very last pic that hasn't even worked the second dose of nitric off yet nothing has been changed , switched , mixed or altered in any way .


The process I'm referring to was removing silver from electrical contacts that was explained to me by Harold amung others .

Out line of process . This is not Harolds precise instructions it is how I did it .

1) weigh contacts .
2) calculate HNO3
3) Add water
4) add heat to water bath and about 25% of the calculated HNO3 and slow cook .
5) cover with a watch glass
6) cook untill all nitric is depleted and cement out with copper . I slow cook a batch for about 24 hours in a crock pot . I add my nitric in small amounts about 25% at a time . I use a very dilute acid mixture for a long slow reaction .

Thats my inturperation of the procedure told to me by Harold and it has worked flawlessly many many times . So before it gets misunderstood that I'm complaining or saying the procedure doesn't work thats not the case . It works great most of the time . What I am saying is this .

It hasn't worked for me everytime . I do not blame the procedure I figure it's the contacts throwing the curve ball . It's worked perfect everytime with sterling cementing out the nicest looking very easy to wash silver anyone could ask for . It's these contacts that throw a curve ball approx 25 % of the time so far .

I agree with you on mixed precipitants but nothing was changed procedure wise . No one changed procedures mid stream . The only thing that was changed was perhaps a different shape contact from one batch to another . It seems apparant to me that some of the contacts are different in composition . I was wondering if anyone had any idea what these precipitants might be .

Every batch so far has had silver in them but sometimes it will not cement out . Sometimes the only way to get it out is with salt . But every batch so far has had silver . Some batches have had a few extra things is my point .

" I can tell by your pictures you are mixing precipitates by changing procedures in mid stride "

That statment is false and very un-true however If that comment was because of the AgCl picture I think I can clarify that some . My filter is long necked and protrudes way down into a quart jar . Once it gets up on the neck it slows filtering way down . So I filter into one jar and when it reaches the neck I filter the rest into another jar . While the second jar was filtering I started adding salt to the first one getting the two layers . Once the second jar was filtered it was dumped into the first jar . But this was the same sloution from the same batch it is not from 2 different batches or 2 different processes . I do have a collection jar my AgCl is dumped into once I'm satisfied it's not something else . The batch with what appears to be 2 layers is currently stored by itself .

I hadn't even noticed the 2 layers untill I dumped the second half of the solution into it . I just found it kinda odd that such a marked line that seemed to seperate two layers was presant .



Steve

I dont know it may be from the copper but I use the same copper everytime . I cook for a way long time like 24 hours so my nitric should be gone . I do cover with a watch glass to get more from the nitric but every batch has been done the same . I do use well water but have used it in every batch so I can't see water being a cause .

Thats what I'm trying to find out here . If it was the copper can you shead some light on what might make the copper do it approx 25% of the time and not the other 75% of the time . Because of that fact it being the copper I use to cement it out with just doesn't seem likley but possable I guess .

I realise I'm new but my only conclusion was some of the contacts had to be different and somehow messing things up . I guess I do ask alot of questions sorry about that . The results were just so weird it leaves me with lots of questions . The reason for 3 post was I figured the more information I could reviel on the matter that it might help someone know what the problem might be .

I'll limit myself to 2 questions

1) You mention the precipitant coming from the copper so my first question is , Any idea what would make the copper do this approx 25% of the time ??

2 ) any idea what the metalic balls are that formed on top of the mud ??

About testing with DMG I'll have to buy some it is on my list of items needed . Do you have that in your store ?? About the AgCl I'm just collecting it for now washing untill the water is clear . Before converting it to metalic silver I'll be sure to boil it good to remove any lead that might be in it . I'll probabbly boil it 3 times for a good long time making sure to keep any lead in solution . This worked great last time on a small amount and did remove lead or possably something else .

The way I did that last time was to boil it right in the crock pot for 4 hours . Drawing it out of the steaming crock pot straight into a filter paper catching my AgCl . It deffently removed something because after the solution cooled a white precipitant was in the bottom of the wash water . I repeated this again cooking for 4 more hours with the only difference being I had no white precipitant after the wash water cooled off the second time . The first wash water did slightly tint a blue color ,the second boiling the water was very clear .

Thanks for clearing up that AgCl stays purple knowing that fairly well answeres any questions I had concerning that . What appeared to be 2 different layers still puzzles me . I know what copper looks like when it precipitates as a white substance . This is not copper in the bottom layer if thats what you ment by the copper doing it . I really have no idea why it seems to be 2 distinct layers but fairly certain this isn't copper . I do think I've had copper fall out of these blue solutions after setting sometime . These always seem like a more grainy of a substance than the white clouds produced by salt or Hcl . Plus they always dropped only after a period of setting for say like 24 hours .


paul

I'm sure Langly is still there and will go back someday when I buy more stuff from them . Anyhow these wern't items in the lab per-say . They were very old 5000 volt dry breakers that supplied electricity to the lab or some other part of the facility . Besides no one at Langley would have a clue as to whats inside something they auctioned off 3 years prior .

I have no idea if it's bismouth / bismith ( sp) but will agree it is something in the jar and I haven't a clue .

 

[Harold_V]

It is difficult to second guess what's going on, but if there's silver in your solution, there's no good reason that it shouldn't cement, regardless of the presence of other substances. I never, in all my years of refining, had a batch fail to cement.

What I am thinking is that you have no free nitric present. It doesn't take much, but without a little, the cementation process seems to be quite retarded. The next time you face this problem, check pH of the solution---and if you find it higher than 1.5 or so, dribble a few drops of nitric in and stir. Note, too, that a heavy concentrated solution often gives problems. A dilute solution will generally behave much better.

Is the surface of your copper quite clean? It there's even a shadow of a doubt, immerse your copper in a heated dilute sulfuric acid solution for a few moments. Copper doesn't dissolve in dilute sulfuric, but copper oxide is dissolved with gusto. That will yield clean copper. No real need to even rinse it off after pickling (that's what it's called, and it's one of the ways copper is cleaned in industry).

Please understand that the following comment is not intended to be negative---especially considering I have a propensity for going on and on on subjects, often saying way too much.

Your posts have been so long and drawn out that I have, more or less, ignored them. Not because I wouldn't like to help---but because I have so little time at my disposal. I try to do as much as I can each day, but when something comes along that's long and drawn out, I have to skim over it and move on. Might be a good idea for you to post a more compact question, and try to restrict each post to one subject matter. Being brief, it will allow a rapid response without trying to sort out several subjects. You've been good about providing information---not leaving anything out that may be important----and that may be why they're so long.

I strongly suggest you avoid making silver chloride unless you have a good reason. Work on cementing until you figure out what the problem is.

As far as contacts go, yes, there's more than one type. Not being a chemist, I have no clue what they contain aside from the waffle backed type having tungsten---but one type gives off a pale yellow substance as it (readily) dissolves. It looks a great deal like silver chloride, but pale yellow.

As a matter of saving time, I never filtered my silver solutions, not even from contacts. I'd allow them to settle briefly, then pour the (relatively) clear solution to my recovery vessel. Traces of solids that follow the solution are removed by flux when the silver is melted. Remember, the recovery procedure is not the final word in purity--the silver cell is.

Harold

 

[Lonnie]

Harold

Thanks so much for a detailed and meaningfull response that means alot to me !! Yes I think I deplete all the nitric or at least thats been my goal . Not bragging but with sterling I've been almost completing a reaction that calls for 200Ml of HNO3 with 150 Ml . Of course I always end up with a few grams of material thats not dissolved . I actually prefer it that way as it tells me the nitric has been depleted . I'll try stiring in a few drops of fresh HNO3 the next time

I wish my picture posting abilities were on this pc at moms but it's not . I'll have to wait untill I can go home to post pics or they would take the whole page . However my solutions have been testing for Pd . I get that green blue color in about every solution . My eyes not the best and I'm not sure this moniter shows up the right colors but the test results sure looks like Pd to me .

Oh I get something everytime I try to cement . But it's not silver or anything like silver and I know silver is in the lot . However reading a message in another post that may just prove to be a great thing . I see where one guy says your PGM's will cement out as a black slime and I have several coffee filters heavy with black slime . This starts out jet black and you can't see any sparkles . After drying in a filter it's kinda a grey black with scattered pieces of sparkling stuff in it . It's very heavy also just about an inch in a test tube weighs 11 grams . Apon heating this it shrinks to about half the volume and is then a metalic grey in color . I'll get pics very soon my sons suppost to come give me a few days break in the morning and I need the break . I dont mind helping mom take care of dad thats not it . It's just that knowing what the end results going to be I can only take it for 10 days to 2 weeks and I have to get away for a few days .

Yes I'm bad for long post but was only trying to mention every detail I could trying to assist someone in helping . Your point is well noted and I'll be sure to be precise and to the point if I ask again for help . So far I've processed about 60 ounces of silver in the last month . 13 troy ounces being sterling and the remainder being from these contacts . About all I bought this last week has been 8 bucks ( face value ) of silver coins and I can't make myself process them . I just love coins to much besides they already in a liquid form . Most likley more liquid than anything I could process and melt despite the purity . Any buyer can look at the coins and know how much silver is involved so it seems they would be more liquid for that reason alone .

One thing about these contacts is I have a few of them that HNO3 is not touching . That tells me theys something in a few of them thats not soluable in nitric . The last batch I did was all of the contacts for their 2 processing . I still have a few contacts that I can not break after 48 hours of nitric processing . Lots of them will break but very hard to break while others just snap into 2 parts with slight finger pressure . I think the silvers been removed and I'm dealing with other metals at this point . Time to do some more Hoke reading and buy some more chemicals .

Thats why I added just a little hcl to that last batch . Still some seem to be untouched but my cooker doesn't really boil good and hard . Yea I see I'm going on and on again so will end it here . Again thanks so much for taking the time to give a detailed and meaningfull response with information I can use .

Lonnie

 

[Lonnie]

With this post from Samuel-a

"" Mario, you can cement the Pd /Pt with a slab of silver, prior to Ag cementation. Use heat to hasten the process. ""

I'm now possitive I have Pd if not Pd and Pt . No doubt in my mind anymore after reading this . My test have been making me think Pd but with the mix of colors plus being new at doing the test I just couldn't be certain . I sure wanted to think so but couldn't be certain .

Back the first time I couldn't get silver to cement out I was racking my brain trying to figure things out . I wondered if I had to much nitric left and ordered some litmus paper . Before it got here I was heating some of the solution thinking I might drive off excess HNO3 if that was the problem .

That wasn't working so I got to thinking if to much nitric is the problem it should dissolve some sterling . So I dropped in a sterling bracelet into the heated jar . Well it never dissolved anything but it did start cementing what I thought was silver and a good little bit of it also .

I should have known it wasn't silver it looked much nicer . This silver I cement out has looked great but looked very much like the crystals the silver cell will grow . This stuff I cemented out was shinnier and more metal looking as opposed to crystal looking . Being the idiot I am I blended it in with my silver LOL shaking my head I guess it doesn't matter much it should be in the silver anyhow and hopfully I'll get it back as a slime when I do run the stuff through a cell .

I have about a good gallon I haven't dropped the AgCl as of yet . You can bet it gets heated and a chunk of silver added to it very soon . It would be started at 6.00 in the morning but I can't . I have an estate sale where lots of sterling is advertised to be at first thing in the morning . Hopfully I'll have some nice pics of some Pd or Pd / Pt mix to post in the next couple of days .

 

[lazersteve]

... This stuff I cemented out was shinnier and more metal looking as opposed to crystal looking ...

Pd precipitates as a black color.

Silver metal is 'whiter' than any other metal when melted aside from Rh. Palladium is a dull gray color when melted.

What you cemented sounds like silver to me.

Cemented silver will come in many shades and colors depending on the concentration of the solution, the temperature, the purity of the copper, contaminates in the solution, etc.

The most definitive test for Pd is to use DMG. Stannous chloride tests for Pd are not conclusive, especially in mixed metal solutions.

Steve

 

[qst42know]

The base metals in sterling will cement a saturated silver nitrate wouldn't it?

 

[Barren Realms 007]

The base metals in sterling will cement a saturated silver nitrate wouldn't it?

Yes untill you run the process and finish removing the base metals that the silver can cement on.

 

[Lonnie]

Well thats all I got tonight when I heated a jar and placed some sterling in is a black precipitate no shinny stuff . When I cooked off my last stock pot thats what I ended up with also black slime . At home now cooking off the latest batch of jugs I've accumulated doing this .

Had a good day bought 9 ounces of sterling I'll process when I get back up to moms to busy trying to play clean up for the next couple days . I'll get the pics you asked for Oz showing the process from one end to the other , however I can't forsee any problems with sterling . I guess I'm glutton for punishment I also bought 1300 grams of contacts today plus the copper they still attatched to . I know the weight simple because I've took these apart before and can just times it by five and be very close . Yea I know more curve balls and headakes but need to be processing something so that will keep me busy for a couple weeks .

Not sure what is worst my picture taking or stannous testing but took some pics . I forgot to get my qtips when I left from moms today so I used an old napkin I had wipping my hands one . I need to get one of them trays with the little impressions in it . I still can't tell much about it I suppose I'll learn that to in time though . I never was expecting anything but silver so if they is extra it's all gravy .

This last batch I added the Hcl to self precipitated 2 different things . One is a grainy yellow stuff while the other is a very light tan mud . This tan mud is something else it's heavy but very finly devided . I'd call it creamy if I had only one word to use .

These pics sure arn't much it was to dark and that dirty napkin didn't help matters any .

In this last picture the drop in the middle of the top row is a drop from solution . The blot on the bottom left is also a drop from solution . On the upper left and far right is where I took a little dab of the stuff that self precipitated and smeared some on the napkin and then dropped a drop of stannous on it . The one on the upper left is the tan mud and the far right is the yellow grainy stuff .

This is the tan mud , it's heavy and settles in just a minute . The yellow stuff is so much heavier that it was easy to seperate the stuff though .

This pic shows the yellow grainy stuff . I know I need better testing supplies and do plan to get one of them dishes for that .

 

[Harold_V]

The base metals in sterling will cement a saturated silver nitrate wouldn't it?

No. Only if they haven't dissolved. Once dissolved, base metals do not cement silver.

Harold

 

[Harold_V]

If the contacts you're processing have a waffle back, the mud in question is likely just tungsten.

Harold

 

[Oz]

Lonnie,
It is not necessary to get me a set of pictures start to finish. I do have difficulty following your posts though since you are discussing multiple starting feedstocks and different results simultaneously. That limits my ability to help you and may be why others are not fast to comment.

When I stated that you were changing procedure in mid stride I was referring to your first post last picture that shows 3 rather distinct layers in your beaker. The bottom being cement silver, the second layer with a purple tint has some silver chloride that has been exposed to UV light that might be contaminated with lead chloride. The top layer, if it has been exposed to the same light for the same amount of time as the rest is almost surely all lead chloride, if not it too is probably silver chloride. The only way this can occur in the same beaker is to go from cementation to precipitation with a chloride. That is changing your procedure in mid stride from my viewpoint.

As you are finding out tungsten, palladium, and rarely platinum are used in silver contact alloys to increase their resistance to heat degradation under high amp loads. Something that has not yet been mentioned in this thread is that cadmium is also a common additive, is also soluble in nitric, and happens to be rather toxic.

As for your spot plate, an inexpensive substitute until you get one is to use disposable white plastic spoons for a spot plate depression. Some reactions are best seen with a black background such as silver and lead chloride, fortunately disposable black plastic spoons are also available.